Sandia National Laboratories and Savannah River National Laboratory have introduced Lithographic Crystallinity Regulation in Additive Fabrication of Thermoplastics (CRAFT), a light...

Sandia National Laboratories and Savannah River National Laboratory have introduced Lithographic Crystallinity Regulation in Additive Fabrication of Thermoplastics (CRAFT), a light-based 3D printing method that modulates polymer crystallinity in real time. By adjusting light intensity during the vat photopolymerization process, the researchers can dynamically alter the molecular structure of resins to produce parts with varying mechanical properties, such as stiffness and flexibility, within a single build. The team, led by Sam Leguizamon and supported by partners including UT Austin, demonstrated the technology by printing a multi-material human hand model featuring rigid internal structures and pliable external tissues in one continuous session. This approach eliminates the need for multi-material assembly or post-processing to achieve functional gradients in thermoplastic components.

This technology addresses a fundamental limitation in current vat photopolymerization and DLP systems, which typically produce parts with uniform material properties. By enabling localized control over crystallinity, CRAFT competes with multi-material jetting technologies that often rely on complex hardware or multiple resin vats to achieve similar functional gradients. The ability to tune material performance via light intensity rather than chemical additives or thermal gradients offers a more streamlined path for producing complex medical models, aerospace components, and protective gear. As the industry moves toward functional integration, this method provides a scalable software-defined approach to material science that reduces the reliance on multi-part assemblies.

For industrial adoption, the primary challenge remains the development of specialized resin formulations that respond predictably to varying light intensities while maintaining print fidelity. Users should evaluate the compatibility of this method with existing high-performance thermoplastics to determine if it can replace traditional multi-material manufacturing workflows. The technology is currently at the research stage and requires further validation regarding build speed and resolution consistency before it can be integrated into commercial production environments.